Browsing by Author "Diedericks, Hanneke"
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- ItemControlled release of an antimicrobial substance from polymeric matrices(Stellenbosch : Stellenbosch University, 2016-03) Diedericks, Hanneke; Van Reenen, Albert Johannes; Cronje, Lizl; Stellenbosch University. Faculty of Science. Department of Chemistry and Polymer ScienceENGLISH ABSTRACT : The main goal of this study was to develop polymeric artifacts (nanofibers and films) infused with an antimicrobial agent, 2,3-dihydroxybenzoic acid and study the release of DHBA as a function of the structure and properties of selected polymers. The effect of hydrophilic and hydrophobic polymers on the release behavior was the main focus of this study. Four different polymers, poly (vinyl alcohol) (PVA), chitosan, poly (ethylene-co-vinyl alcohol) (EVOH) and poly (styrene-co-maleic anhydride) (SMA); all different in their hydrophilic-hydrophobic nature were used. Controlling the release of DHBA from these polymers have however not been investigated to our knowledge. Various parameters can influence the release of an agent from a matrix, which includes the type of polymer used and interactions between the polymer and the agent. To effectively study the release of DHBA from electrospun nanofibers, it was important for the different polymer nanofibers to have similar average fiber diameters. This was done by investigating the effect different electrospinning parameters has on the fiber diameter. Incorporation of DHBA into the polymer artifacts (films and nanofibers) was successful with minimum loss of the agent. Interaction between polymer and agent was confirmed using FTIR. The interaction can be ascribed to the size of the molecular structure of the polymers, the smaller molecules showed hydrogen bonding with the agent with the larger molecules, limited interaction was observed. Thermal analysis of the matrices was studied using techniques such as DSC and TGA. These results revealed changes in the stability of the DHBA-loaded matrices compared to the pure polymer matrix. These changes can be attributed to the interaction between the polymer and the agent. The release of DHBA from the films and nanofibers was investigated using UV spectroscopy. A burst release was observed which is explained by the type of polymer used. Although the burst release of this agent has been documented, the ability to control the release of DHBA has not been done. Controlling the release of DHBA from the films and nanofibers was done by a coating process. SEM and FTIR were used to confirm the successful coating of these nanofibers. These coated nanofibers showed retardation of the release of DHBA. The more hydrophilic polymer used showed the greatest effect on the release behavior. These results confirmed the effect the type of polymer used has on the release of DHBA.